A graphical user interface (GUI) is a human-computer interface which is used to interact with computer applications. A GUI typically uses windows, icons and menus which can be manipulated by a mouse and/or keyboard to provide certain functions.
A window is a portion of the monitor screen that can display its contents (e.g., a program, icons, a text file or an image) independently of the rest of the display screen. Multiple windows can be open simultaneously. Each window can display a different application, or each can display different files (e.g., text, image or spreadsheet files) that have been opened or created with a single application.
An icon is a small picture or symbol in a GUI that represents a program, a command, a file, a directory or a device (such as a hard disk or floppy). Icons are used both on the desktop and within application programs. Examples include small rectangles (to represent files), file folders (to represent directories), a trash can (to indicate a place to dispose of unwanted files and directories) and buttons on web browsers (for navigating to previous pages, for reloading the current page, etc.).
Commands are issued in the GUI by using a mouse, trackball, touch pad or keyboard to first move a pointer on the screen to, or on top of, the icon, menu item or window of interest in order to select that object. Then, for example, icons and windows can be moved by dragging (moving the mouse with the mouse button held down) and objects or programs can be opened by clicking on their icons.
GUIs may also allow a user to call up a dialog box or panel which is typically a small temporary window in a graphical user interface that appears in order to request information from the user. After the information has been provided, the user can dismiss the dialog box.
GUIs make computer operation more intuitive, and thus easier to learn and use. For example, it is much easier for a new user to move a file from one directory to another by dragging its icon with the mouse than by having to remember and type commands to accomplish the same task.
GUIs generally provide users with immediate, visual feedback about the effect of each action. For example, when a user deletes an icon representing a file, the icon immediately disappears, confirming that the file has been deleted (or at least sent to the trash can). This contrasts with the situation for a Command Line Interface (CLI), in which the user types a delete command (inclusive of the name of the file to be deleted) but receives no automatic feedback indicating that the file has actually been removed.
In addition, GUIs allow users to take full advantage of the powerful multitasking (the ability for multiple programs and/or multiple instances of single programs to run simultaneously) capabilities of modern operating systems by allowing such multiple programs and/or instances to be displayed simultaneously. The result is a large increase in the flexibility of computer use and a consequent rise in user productivity.
The use of Graphical User Interfaces (GUIs) is ubiquitous. GUIs are used for all types of computer related operations and applications, as they provide a user-friendly and easily usable manner for presenting information to and receiving instructions from a user.